Star couplers are used in high-speed, multiple access optical networks since they evenly distribute an input signal among many receivers and makes possible the interconnection between them. A star coupler comprises two arrays of channel waveguides (an input array and an output array) separated by a slab waveguide. The output power from any of N fibers connected to the input array is radiated in the slab and received efficiently by the output array of fibers.
The recent increase of interest in polymer optical fibers (POF) was primarily driven by the belief that large core polymer optical fibers may become a cost-effective short distance interconnect solution for many data communication applications as described, for example, in an article by Y. Koike et al entitled "High-Bandwidth Graded-Index Polymer Optical Fiber" in IEEE Journal of Lightwave Technology, Vol. 13, pp. 1475-1489, 1995. It has been shown that material, production, as well as connection costs associated with polymer optical fibers are appreciably lower than those of glass fibers. Moreover, when polymer optical fibers are more widely accepted, these costs can be further reduced and become comparable to the costs of copper transmission lines of similar bandwidth. While research on finding low-loss polymer optical fibers materials and low-cost production methods is actively being pursued as shown, for instance, in an article by S. Yamazaki et al entitled "A 2.5 GB/s 100 m GRIN Plastic Optical Fiber Data Link at 650 nm Wavelength", in Graded Index POF, (Information Gatekeepers, Boston, 1996), pp. 98-101 and in an article by T. Ishgure et al entitled "Large-Core High-Bandwidth Polymer Optical Fiber and Its Applications", in Technical Digest of CLEO/Europe '94, paper CThD5, attention has also been drawn to low-cost connection schemes. Large core size, and high material flexibility provide many opportunities to decrease coupling and connection costs for polymer optical fibers. Etched-mirror-based side-couplings have been used to couple light in or out of polymer optical fibers cost-effectively. See for example, an article by Y. Li et al entitled "Distribution of Light and Optical Signals Using Embedded Mirrors Inside Polymer Optical Fibers" in Photon Technol. Lett, vol. 8, pp. 1352-1354, 1996 and an article by Y. Li et al entitled "4.times.16 Polymer Fiber Optical Array Couplers", in IEEE Photon. Technol. Lett., vol. 8, pp. 1651-1652, 1996.